Acinetobacter sp. Y1的氨氮去除性能及其关键酶活性

Ammonia nitrogen removal characteristic and its key enzymes activity of Acinetobacter sp. Y1

摘要:

【目的】研究Acinetobacter sp. Y1的氨氮(NH4+-N)去除性能及其关键酶的提取与酶活性。【方法】以柠檬酸钠为碳源，硫酸铵为氮源，研究菌株Y1的NH4+-N去除性能；采用正交实验优化超声波破碎法提取粗酶的条件，SDS-PAGE分析比较渗透压休克法和超声波破碎法获得的粗酶；检测关键酶——羟胺氧化还原酶(HAO)、亚硝酸盐还原酶(NIR)、硝酸盐还原酶(NAR)的酶活性。【结果】24 h内菌株Y1的菌密度(OD600)可达1.280，对NH4+-N、总氮(TN)和COD的降解率分别达到98%、94%和92%，硝化过程中羟胺、亚硝酸盐氮、硝酸盐氮不积累，反硝化产生N2；超声波破碎法提取粗酶的最佳工作条件为：破碎功率50 W，工作与间歇时间分别为4 s和7 s，OD600为1.250，总工作时间20 min，关键酶HAO、NIR和NAR的比活力分别为0.011、0.002和0.018 U/mg；渗透压休克法得到的HAO比活力是0.067 U/mg。【结论】Acinetobacter sp. Y1能同时高效去除NH4+-N、TN和COD。优化超声波破碎法提取粗酶的条件，检测到HAO、NIR和NAR的酶活性，且渗透压休克法比超声波破碎法更适合用来提取HAO。

Abstract:

[Objective] To study the ammonia nitrogen (NH4+-N) removal characteristic, extraction and activity of its key enzymes in Acinetobacter sp. Y1. [Methods] Sodium citrate and ammonium sulfate were used as the sole carbon and nitrogen sources respectively to investigate NH4+-N removal characteristic of strain Y1. The ultrasonic conditions were optimized using orthogonal experiment, and the crude enzyme obtained from ultrasonic crushing method and osmotic shock method were compared by SDS-PAGE, then the activity of key enzymes——hydroxylamine oxidoreductase (HAO), nitrite reductase (NIR) and nitrate reductase (NAR) were measured. [Results] Bacteria density (OD600) was 1.280, and NH4+-N, total nitrogen (TN), COD removal rate can reach up to 98%, 94% and 92% respectively of strain Y1 in 24 h. Hydroxylamine, nitrite nitrogen and nitrate nitrogen in nitrification process were detected without accumulation, and N2 was produced in the process of denitrification. The optimal ultrasonic conditions were: ultrasonic power 50 W, work/interval time 4/7 s, OD600=1.250 and total working time 20 min, and the corresponding specific activities of HAO, NIR and NAR were 0.011, 0.002, 0.018 U/mg, respectively. Specific activity of HAO obtained by osmotic shock method was 0.067 U/mg. [Conclusion] NH4+-N, TN and COD were removed simultaneously with high efficiency by strain Y1. HAO, NIR and NAR activities were detected after optimizing the ultrasonic conditions. And it was better to use osmotic shock method for HAO extraction than ultrasonic crushing method.